基于TrustZone技术和μCLinux的安全嵌入式系统设计与实现

深入分析了TrustZone技术和μCLinux操作系统在构建嵌入系统时存在的不足,并针对其安全缺陷,利用LSM框架,采用DTE模型和BLP模型实现了μCLinux操作系统的安全增强,从而在操作系统层解决了TrustZone技术存在的安全问题,在此基础上,提出了基于TrustZone技术和安全增强的μCLinux操作系统的安全嵌入式系统框架,并对其具体实现进行了简要介绍。     

基于TrustZone技术和μCLinux的安全嵌入式系统设计与实现*

深入分析了TrustZone技术和μCLinux操作系统在构建嵌入系统时存在的不足,并针对其安全缺陷,利用LSM框架,采用DTE模型和BLP模型实现了μCLinux操作系统的安全增强,从而在操作系统层解决了TrustZone技术存在的安全问题,在此基础上,提出了基于TrustZone 技术和安全增强的μCLinux操作系统的安全嵌入式系统框架,并对其具体实现进行了简要介绍。     

支持网格的机群操作系统的设计

机群操作系统面临着网格计算对其提出的资源共享、协同工作和自治管理的挑战，现有的扁平机群操作系统不能够适应这种需求，提出了一种基于服务的机群操作系统DCOS，采用层次型结构和面向对象的设计思想，从多个角度为网络系统提供支持，讨论了远程过程调用、系统状态侦测、实时检查点、安全机制等主要关键技术。     

IDS:企业的安全误区

诚然,入侵侦测系统(IDS)可以具有很好的监视及侦测入侵的能力,也可以对企业或组织的安全提供很好的协助。但是,随着入侵侦测系统的出现,许多针对网络入侵侦测系统的规避手法也随之不断“升级”。 对比已知攻击手法与入侵侦测系     

一种新型的防火墙系统

利用防火墙技术来增强网络安全性越来越得到人们的青睐,但目前的防火墙技术不能有效地解决网络内部安全的问题。针对这一问题,该文提出了一种新型的防火墙系统－－ＥＲＣＩＳＴ＿Ｂ２防火墙系统,它结合了目前流行的防火墙技术－－包过滤、代理、虚拟网关,并将代理服务器和认证系统建立在Ｂ２级操作系统上,使防火墙技术和操作系统有机地结合起来,从而利用操作系统的安全机制达到解决系统内部安全的目的。     

让安全直达系统核心

11月初,浪潮信息安全宣布针对服务器操作系统进行安全加固的S S R产品全面上市,从根本上抵御了目前各种针对操作系统的攻击行为,彻底防止病毒、蠕虫、黑客攻击等对操作系统和数据库的破坏。浪潮信息安全自主研发的这款S S R产品的成功上市,填补了服务器操作系统的安全防护体系的空白。众所周知,信息安全防护体系按照不同应用情况和网络结构,可划分为物理层、系统层、网络层、应用层和管理层的防护。但目前国内主流信息安全产品,包括防火墙、IDS/IPS等都仅仅是针对网络层进行安全防护,防病毒、CA/P K I针对应用层进行防护,在操作系统…     

基于文件系统过滤驱动的加密系统设计与实现

针对传统应用层加密系统每次使用都需要输入口令,使用复杂且安全性不高,而设备驱动层加密系统紧耦合于操作系统及其组件,实现繁杂等问题,在Windows NT内核框架下利用文件系统过滤驱动实现数据加解密的安全保护系统。结果证明可以对存取中的数据进行动态透明的加解密,使用方便安全,支持多种文件系统。从安全性和性能上对比了该加密系统与Windows EFS加密文件系统。     

Sysprep技术在医院工作站操作系统部署中的应用探讨

在我国卫生行业信息系统安全等级保护安全建设整改的阶段,医院信息系统内的工作站大都可能需要重新安装操作系统、安全软件、医用软件等问题。同时,在医院信息系统维护中,也常会遇到因为软件升级、补丁更新、破坏性的病毒、医务人员误操作等导致的系统问题,常需要重新安装操作系统才能解决。针对上述过程中安装操作系统及相关软件的繁琐、重复、费时等问题,介绍了如何利用Sysprep系统封装技术对Windows系统封装,根据实际需求制作GHO镜像文件,实现操作系统的快速部署。     

国标四级安全操作系统的内存泄露分析方法研究

该文首先简要介绍了国家标准（GB/T20271-2006、GB/T20272-2006等）对四级操作系统进行中抵抗力分析的要求,进而针对操作系统内存泄露缺陷提出了动态系统化搜索的方法。该文论述了笔者在研发国标四级操作系统＂方德方舟安全操作系统＂（NFSARK）的过程中,针对系统内存泄露采用的分析方法。     

Context-sensitive distraction warnings – Effects on drivers׳ visual behavior and acceptance

In this study, we investigated the effects of context-sensitive distraction warnings on drivers׳ in-car glance behaviors and acceptance. The studied prototype warning application functions on a smart phone. The novelty of the application is its proactive and context-sensitive approach to the adjustment of warning thresholds according to the estimated visual demands of the driving situation ahead. In our study, novice and experienced drivers conducted in-car tasks with a smart phone on a test track with and without the warnings. The application gave a warning if the driver׳s gaze was recognized to remain on the smart phone over a situation-specific threshold time, or if the driver was approaching a high-demand part of the track (an intersection or a tight curve). Glance metrics indicated a significant increasing effect of the warnings on glance time on road while multitasking. The effect varied between 5% and 30% increase depending on the in-car task. A text message reading task was the most visually demanding activity and indicated the greatest effect of the warnings on glance time on road. Driving experience did not have an effect on the efficiency of the warnings. The proposed gaze tracking with current smart phone technology proved to be highly unreliable in varying lighting conditions. However, the findings suggest that location-based proactive distraction warnings of high-demanding driving situations ahead could help all drivers in overcoming the inability to evaluate situational demands while interacting with complex in-car tasks and to place more attention on the road. Furthermore, survey results indicate that it is possible to achieve high levels of trust, perceived usefulness, and acceptance with these kinds of context-sensitive distraction warnings for drivers.     

Detecting logical argumentation in text via communicative discourse tree

We solve the argument mining problem by investigating discourse and communicative text structure. A new formal graph-based structure called communicative discourse tree (CDT) is defined. It consists of a discourse tree with additional labels on edges, which stand for verbs. These verbs represent communicative actions. Discourse trees are based on rhetoric relations, extracted from a text according to Rhetoric Structure Theory. The problem is tackled as a binary classification task, where the positive class corresponds to texts with arguments and the negative class corresponds to texts with no arguments. The feature engineering for the classification task is conducted, deciding on which syntactic and discourse features are associated with logical argumentation. Text classification framework based on syntactic, discourse and communicative discourse text structures with a number of learning approaches is implemented. Evaluation on a combined data-set is provided.     

Gait generation and control for biped robots with underactuation degree one

The paper develops a unified feedback control law for n degree-of-freedom biped robots with one degree of underactuation so as to generate periodic orbits on different slopes. The periodic orbits on different slopes are produced from an original periodic orbit, which is either a natural passive limit cycle on a specific slope or a stable periodic walking gait on level ground generated with active control. First, inspired by the controlled symmetries approach, a general result on gait generation on different slopes based on a periodic orbit on a specific slope is obtained. Second, the time-scaling control approach is integrated to reproduce geometrically same periodic orbits for biped robots with one degree of underactuation. The degree of underactuation is compensated by one degree-of-freedom in the temporal evolution that scales the original periodic orbit. Necessary and sufficient conditions are investigated for the existence and stability properties of periodic orbits on different slopes with the proposed control law. Finally, the proposed approach is illustrated by two kinds of underactuated biped robots: one has a passive gait on a specific ground slope and the other does not have a natural passive gait.     

Impact of backpack type on respiratory muscle strength and lung function in children

We examine the influence of backpack type on lung function and respiratory muscle strength in children. Thirty-seven children were assessed for lung function and inspiratory and expiratory muscle strength under four randomly determined conditions: unloaded erect standing and three conditions carrying 15% of the child's body weight. In these three conditions, children carried the weight on a backpack with bilateral shoulder straps carried over both shoulders, on a backpack with bilateral shoulder straps carried over one shoulder and on a backpack with a mono shoulder strap. Significantly lower forced vital capacity, forced expiratory volume in one second and maximal expiratory pressure were observed when children carried a backpack with a mono shoulder strap compared to the unloaded standing position. In conclusion, the restrictive effect and the decrease in expiratory muscle strength were more pronounced for the backpack with a mono shoulder strap, suggesting that a double strap backpack is preferable to a mono shoulder strap backpack.

Practitioner summary: There is little known about the effect of schoolbags on respiratory muscle function. We investigated the influence of backpack type on lung function and respiratory muscle strength. A backpack with a mono shoulder strap created a restrictive effect and a decrease in strength, suggesting that a double strap backpack is preferable to a mono shoulder strap backpack.     

Connecting PEACE to UNIX

The SUPRENUM-machine consists of two components with different operating systems: a host (STR) with UNIX V.3 and a high-performance kernel (HLK) with PEACE. SUPRENUM-programs will be started on the STR and executed mainly on the HLK. Every communication with the outside world will run through the STR. Suprenum-programs are distributed programs. In general, processes of a SUPRENUM-program will be executed on different processing nodes of different clusters of the HLK. For some of these processes, especially those which communicate with the world, it seems to be useful to be executed on the STR. To provide this, parts of PEACE will be emulated in UNIX V. By doing this one achieves that STR and HLK form a single machine from the viewpoint of the user. In addition, this provides the user with the possibility to develop and test his program on the STR and after that run it on the HLK. The transformation on the HLK will be achieved by the usage of a different library.     

Compliant motion using a mobile manipulator: an operational space formulation approach to aircraft canopy polishing

The operational space formulation provides a framework for the analysis and control of robotic systems with respect to interactions with their environments. In this paper, we discuss its implementation on a mobile manipulator programmed to polish an aircraft canopy with a curved surface of unknown geometry. The polishing task requires the robot to apply a specified normal force on the canopy surface while simultaneously performing a compliant motion keeping the surface of the grinding tool tangentially in contact with the workpiece. A human operator controls the mobile base via a joystick to guide the polishing tool to desired areas on the canopy surface, effectively increasing the mobile manipulator's reachable workspace. The results demonstrate the efficacy of compliant motion and force regulation based on the operational space formulation for robots performing tasks in unknown environments with robustness towards base motion disturbances. The mobile manipulator consists of a PUMA 560 arm mounted on top of a Nomad XR4000 mobile base. Implementation issues are discussed and experimental results are shown.     

Stability of Local On‐Ramp Metering Control Laws

A framework for stability analysis of local on‐ramp metering control strategies based on the cell transmission model is presented. Within this framework, it is possible to formulate Lyapunov and input‐state stability results for on‐ramp metering control strategies in an open section of highway with on‐ramps. Using this analysis, recommendations for the design of on‐ramp metering control laws set points are derived. Two examples on the use of such analysis are presented. One deals with the stability analysis of a local on‐ramp metering control law and the other with the design of a disturbance observer that, used in combination with the local on‐ramp metering control law, provides a more robust response to traffic regulation. Simulation results are included that confirm the possibility of using this framework to test the impact of local on‐ramp metering control strategies.     

Computational performance of a parallelized three-dimensional high-order spectral element toolbox

In this paper, a comprehensive performance review of an MPI-based high-order three-dimensional spectral element method C++ toolbox is presented. The focus is put on the performance evaluation of several aspects with a particular emphasis on the parallel efficiency. The performance evaluation is analyzed with the help of a time prediction model based on a parameterization of the application and the hardware resources. Two tailor-made benchmark cases in computational fluid dynamics (CFD) are introduced and used to carry out this review, stressing the particular interest for clusters with up to thousands of cores. Some problems in the parallel implementation have been detected and corrected. The theoretical complexities with respect to the number of elements, to the polynomial degree, and to communication needs are correctly reproduced. It is concluded that this type of code has a nearly perfect speedup on machines with thousands of cores, and is ready to make the step to next-generation petaFLOP machines.     

基于多分类和ResNet的不良图片识别框架

针对实际应用中色情图片的复杂多样性问题,提出一种基于多分类和深度残差网络（ResNet）的不良图片识别框架.不同于已有的方法将色情图片识别作为二分类问题,该方法基于多样性特征将色情图片分为7个更细粒度的类别,并将正常图片分为是否包含人物2个类别,通过50层ResNet模型进行分类,再按照阈值计算是否属于不良图片.为了减少训练时间和挖掘优质特征,采用一种反馈修正的训练策略.提出一种单边滑动窗口的预处理方法以解决图片不同尺度的影响问题.测试结果表明,该方法在时间效率和识别准确率上效果良好.